Package structure and method for fabricating the same

Abstract

A package structure includes a die and a first encapsulant. The first encapsulant surrounds the die. The first encapsulant includes a first polymeric material and a first material network in the first polymeric material. The first material network comprises a first cellulose nanofibrils (CNFs) and a first 2D material, and the first 2D material has an in-plane thermal conductivity greater than a thermal conductivity of the first polymeric material.

What is claimed is: 
     
         1 . A package structure, comprising:
 a die; and   a first encapsulant surrounding the die, wherein the first encapsulant comprises:
 a first polymeric material; and 
 a first material network in the first polymeric material, wherein the first material network comprises a first cellulose nanofibrils (CNFs) and a first 2D material, and the first 2D material has an in-plane thermal conductivity greater than a thermal conductivity of the first polymeric material. 
   
     
     
         2 . The package structure of  claim 1 , wherein the first 2D material has an out-of-plane thermal conductivity greater than the thermal conductivity of the first polymeric material. 
     
     
         3 . The package structure of  claim 1 , wherein a dielectric constant of the first encapsulant is lower than silicon dioxide. 
     
     
         4 . The package structure of  claim 1 , wherein the first 2D material comprises hexagonal boron nitride. 
     
     
         5 . The package structure of  claim 1 , further comprising:
 a second encapsulant surrounding the die and the first encapsulant, wherein the second encapsulant comprises a second polymeric material a second material network in the second polymeric material, and the second material network comprises a second CNFs and a second 2D material, the second 2D material has an in-plane thermal conductivity greater than a thermal conductivity of the second polymeric material.   
     
     
         6 . The package structure of  claim 5 , wherein the second 2D material of the second encapsulant is different from the first 2D material of the first encapsulant. 
     
     
         7 . The package structure of  claim 5 , wherein the second 2D material has a higher electrical conductivity than that of the first 2D material. 
     
     
         8 . The package structure of  claim 5 , wherein the second 2D material comprises graphene. 
     
     
         9 . The package structure of  claim 1 , further comprising:
 a package substrate underlying the die; and   an underfill between the package substrate and the die, wherein the underfill comprises a second polymeric material and a second material network in the second polymeric material, and the second material network comprises a second CNFs and a second 2D material.   
     
     
         10 . The package structure of  claim 9 , wherein a premixing weight ratio of the second CNFs to the second 2D material of the underfill is different than a premixing weight ratio of the first CNFs to the first 2D material of the first encapsulant. 
     
     
         11 . A package structure, comprising:
 a package substrate;   a die disposed over the package substrate;   a underfill disposed between the package substrate and the die, wherein the underfill comprises a first 1D nanomaterial and a first 2D material; and   a first encapsulant disposed over the package substrate and laterally surrounding the die and the underfill, wherein the first encapsulant comprises a second 1D nanomaterial and a second 2D material that is different from the first 2D material of the underfill.   
     
     
         12 . The package structure of  claim 11 , wherein the first 2D material of the underfill comprises hexagonal boron nitride, and the second 2D material of the first encapsulant comprises graphene. 
     
     
         13 . The package structure of  claim 11 , wherein a dielectric constant of the first encapsulant is lower than silicon dioxide. 
     
     
         14 . The package structure of  claim 11 , further comprising:
 a second encapsulant disposed between the die and the first encapsulant and laterally surrounding the die, where the second encapsulant comprises a third 1D nanomaterial and a third 2D material.   
     
     
         15 . The package structure of  claim 14 , wherein the third 2D material of the second encapsulant is different from the second 2D material of the first encapsulant. 
     
     
         16 . A package structure, comprising:
 a package substrate;   a die disposed over the package substrate;   a underfill disposed between the package substrate and the die, wherein the underfill comprises a first 1D nanomaterial and a first 2D material; and   a first encapsulant laterally surrounding the die, wherein the first encapsulant comprises a second 1D nanomaterial and a second 2D material, and a premixing weight ratio of the second 1D nanomaterial to the second 2D material of the first encapsulant is different from a premixing weight ratio of the first 1D nanomaterial to the first 2D material of the underfill.   
     
     
         17 . The package structure of  claim 16 , wherein the first 1D nanomaterial comprises carbon nanotubes. 
     
     
         18 . The package structure of  claim 16 , wherein a dielectric constant of the underfill is lower than silicon dioxide. 
     
     
         19 . The package structure of  claim 16 , wherein the second 2D material of the first encapsulant is different from the first 1D nanomaterial of the underfill. 
     
     
         20 . The package structure of  claim 16 . wherein the second 2D material of the first encapsulant is the same as the first 1D nanomaterial of the underfill.